how to use the constant function from the underscore library in javascript

To use the constant function from the Underscore library in JavaScript, you first need to include the Underscore library in your project. You can do this by downloading the library and adding it as a script tag in your HTML code or by installing it via a package manager such as NPM.

Once you have the Underscore library included in your project, you can use the constant function to create a new function that always returns the same value. Here's an example:

index.tsx
const _ = require('underscore');

// Create a new function that always returns the number 42
const always42 = _.constant(42);

console.log(always42()); // Output: 42
console.log(always42()); // Output: 42
console.log(always42()); // Output: 42
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In this example, we first import the Underscore library using the require function. We then use the constant function to create a new function called always42 that always returns the number 42. We can call this function multiple times, and it will always return the same value.

The constant function can be useful in functional programming when you need to create a function that always returns the same value, such as a default value for a function parameter or a default value for an object property.